1. Field of the Invention
The present invention generally relates to providing and operating numerous source devices such as sensors as part of a network or part of the Internet of Things (IoT) or, more generally, any electronic device with a memory chip (or memory) such as a television, a home or business appliance or piece of equipment, and the like and, more particularly, to a method and corresponding system adapted to enable physical objects or devices (labeled “source devices” herein and intended to include any electronic device with memory (e.g., a memory chip)) to know their specific location and to report this information out (e.g., as part of periodic reporting to a central server/monitoring device and/or in response to queries for other data (such as sensor readings/measurements).
2. Relevant Background
The Internet of Things (IoT) is the network of physical devices embedded with electronics, software/hardware, and network connectivity (typically, wireless communication abilities) that enable these physical devices or objects to collect and exchange data. The IoT allows objects to be sensed and controlled remotely across existing network infrastructure, and this creates opportunities for more direct integration of the physical world into computer-based systems. The IoT can be used in many ways such as to provide smart grids, smart homes, intelligent transportation, and smart cities. Each “thing” or source device is uniquely identifiable through its embedded computing system but is able to interoperate within the existing Internet infrastructure, and some experts estimate that the IoT will include fifty billion source devices by 2020.
Wireless Sensor Networks (WSNs) provide one specific example of the IoT. WSNs are typically made up of thousands to millions of small, low cost devices (e.g., sensors). Each device is typically battery powered and has limited processing and memory resources and transfers or reports sensor data limited by a relatively small packet payload size. WSNs may have a wide variety of uses such as structural health monitoring (e.g., with strain gages/sensors), water system monitoring (e.g., with pressure sensors and the like), energy monitoring, machine condition monitoring, and transportation management. Connecting networks of these source devices directly to the Internet to transfer sensor data to Internet users is useful to allow the users to observe data in real time to monitor and manage diverse systems and equipment.
In the IoT, there are many situations where it is desirable or even critical to know the precise geographic (or physical) location of the thing or source device. In many WSN applications, it is important, such as for environmental surveillance and disaster management, to have the location of each of the sensors in the WSN. One solution would be to equip each source device with a global navigation satellite system (GNSS) receiver such as a GPS receiver to provide location information for the source device, but this is generally a much too costly solution in terms of money and energy consumption. For example, a city may install a multitude of stationary sensors on their water system or a train company may apply sensors along their train tracks in numerous locations, and even a small reduction in cost may make such a WSN desirable from a cost perspective. Presently, each source device can be fabricated to determine its location with a GPS chip and an antenna at a cost of about $1 to $10 USD per sensor. This positioning ability, hence, can significantly and unacceptably increase the cost of the WSN when large numbers of sensors are utilized (e.g., many thousands or millions may be used in some WSNs). Further, GPS receivers often fail inside buildings and under heavy vegetative cover such that the location data would be unavailable or inaccurate, and many WSNs include sensors in such settings where their data may be unavailable or inaccurate.
Another solution for providing locations of sensors is to have each sensor location manually determined and recorded by the installing technician such as on a notebook and later transcribed in a central database. This sensor location data can then be linked at a central server or monitoring station to each of the sensors of a WSN (or source devices in the IoT). However, this approach is time consuming and inefficient, and the technicians may make errors in determining a physical location or writing the location down or in recording/storing locations for some sensors (or even forget to store this data for some of the sensors). As a result, the manual localization solution generally is not acceptable for use in WSNs even when relatively small numbers of sensors are networked together.
Hence, there remains a need for an improved method for determining the physical location (e.g., X-Y or geospatial coordinates that may include altitude) of a sensor or other source device, for storing this location information (or data), and for reporting the location information out to other devices in the network (e.g., to a central monitoring station or server or to a workstation via the Internet/cloud).